Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/18—Water
  • G01N33/1826—Organic contamination in water
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/0004—Gaseous mixtures, e.g. polluted air
  • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
  • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
  • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
  • G01N33/0047—Organic compounds
  • G01N33/0049—Halogenated organic compounds
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/22—Devices for withdrawing samples in the gaseous state
  • G01N1/2226—Sampling from a closed space, e.g. food package, head space
  • G01N2001/2229—Headspace sampling, i.e. vapour over liquid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
  • G01N1/40—Concentrating samples
  • G01N1/4055—Concentrating samples by solubility techniques
  • G01N2001/4066—Concentrating samples by solubility techniques using difference of solubility between liquid and gas, e.g. bubbling, scrubbing or sparging
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/20—Controlling water pollution; Waste water treatment

Definitions

• the present invention relates to systems and methods for monitoring the concentration of a volatile, weakly soluble material dissolved in a liquid such as wastewater.
• wastewater is then discharged as effluent into nearby streams and rivers.
• the wastewater discharged contains some type of organic material.
• the material is transferred from the liquid phase to the gas phase.
• the gas from the gas phase is swept through a sorbent trap where the material is trapped.
• the trap is heated and backflushed with the inert gas to desorb the material into an analytical instrument, such as a gas chromatograph, which monitors the concentration of the material.
• the gas chromatograph is temperature programmed to separate the material. The gas is then released from the system to the atmosphere.
• This system also samples relatively small volumes of liquid, and thus, as in the above-described system, is not sufficient to ensure high sensitivity of the concentration measurement. Also, this system uses relatively small diameter piping (e.g., piping having a 1/16" outer
• the system comprises a vessel including a liquid space containing the liquid and a head space containing gas disposed above the surface of the liquid, liquid inlet means disposed in
• liquid outlet means for enhancing the transfer of the volatile material from the liquid phase to the gas phase
• liquid outlet port formed in the vessel and a liquid discharge conduit disposed in
• liquid discharge conduit configured to maintain the volume of the liquid within the vessel
• means for removing a portion of the gas contained in the head space from the vessel means for measuring the concentration of the material in the gas removed from the head space, means for calculating a gas phase concentration value from the measured concentration and for converting the gas phase concentration value to a liquid phase concentration value and means for re-introducing the gas into the vessel, thereby continuing to enhance the transfer of the material from the liquid phase to the gas phase.
• a method for monitoring the concentration of volatile material dissolved in a liquid comprises the steps of
• the system in accordance with a second embodiment of the present invention comprises a vessel including a liquid space containing a sample of the liquid and a head space containing gas disposed above the surface of the liquid, liquid inlet means disposed in communication with the head space for introducing the sample of the liquid into the vessel, means for removing a portion of the gas contained in the head space from the vessel, means for measuring the concentration of the material in the gas removed from the head space, means for calculating a gas phase concentration value from the measured concentration and for converting the gas phase concentration value to a liquid phase concentration value, means for re-introducing the gas into the vessel to create bubbles in the liquid, thereby enhancing the transfer of the volatile material from the liquid phase to the gas phase and liquid outlet means including a liquid outlet port formed in the vessel and a liquid discharge conduit disposed in communication with the liquid outlet port for discharging the sample of the liquid from the vessel, the liquid discharge conduit being configured to maintain the volume of the liquid in the vessel constant.
• a sample of the liquid into a vessel including a liquid space, containing the sample of the liquid and a head space containing gas disposed above the surface of the liquid, removing a portion of gas in the head space from the vessel, measuring the concentration of the material in the gas removed from the head space, calculating a gas phase concentration value from the measured concentration, converting the gas phase concentration value to a liquid phase
• concentration value re-introducing the gas into the vessel to create bubbles in the liquid, thereby enhancing the transfer of material from the liquid phase to the gas phase and discharging the sample of the liquid from the vessel.
• the system of the present invention in accordance with a third embodiment comprises a vessel including a liquid space containing the liquid and a head space containing gas disposed above the surface of the liquid, liquid inlet means disposed in communication with the head space for injecting a stream of the liquid into the vessel at a sufficient velocity to create bubbles and
• liquid outlet means for enhancing the transfer of the volatile material from the liquid phase to the gas phase
• liquid outlet port formed in the vessel and a liquid discharge conduit disposed in
• the liquid discharge conduit being configured to maintain the volume of the liquid within the vessel constant, means for removing a portion of the gas contained in the head space from the vessel, means for measuring the concentration of material in the gas removed from the head space, means for calculating a gas phase concentration value from the measured concentration and for converting the gas phase concentration value to a liquid phase concentration value and means for discharging the gas to the atmosphere.
• a method for monitoring the concentration of volatile material dissolved in a liquid comprises the steps of injecting a stream of the liquid into a vessel including a liquid space containing the liquid and a head space containing gas at a sufficient velocity to create bubbles and turbulence in the liquid, thereby enhancing the transfer of the material from the liquid phase to the gas phase, discharging the liquid from the vessel, removing a portion of the gas contained in the head space from the vessel, measuring the concentration of the material in the gas removed from the head space, calculating the gas phase concentration from the measured concentration, converting the gas phase concentration value to a liquid phase concentration value and discharging the gas to the atmosphere.
• Fig. 1 is a schematic view of a system for monitoring the concentration of volatile material dissolved in a liquid according to a first or preferred embodiment of the present invention.
• Fig. 2 is a schematic view of a second embodiment of the system of the present invention.
• Fig. 3 is a schematic view of a third embodiment of the system of the present invention.
• Fig. 4 is a flow chart for the numerical computations for calculating a gas phase
• Fig. 4A is a flow chart for the numerical computations of block 3 of the flow chart of Fig. 4 for calculating the liquid phase concentration value.
• Fig. 5 is a graph illustrating the concentration of CCI 4 and CHCl 3 in wastewater during an intentional excursion of the wastewater of the system of the preferred embodiment of the present invention.
• Fig. 6 is a graph illustrating the concentration of CCI 4 and CHCI 3 during an
• Appendix A is the source code for the computations shown in the flowchart of Fig. 4a. DESCRIPTION OF THE PREFERRED EMBODIMENTS
• a system for monitoring the concentration of volatile material dissolved in a liquid in accordance with a first or preferred embodiment of the present invention, there is provided a system for monitoring the concentration of volatile material dissolved in a liquid.
• System 10 comprises a vessel 12 including a liquid space 14 which contains the liquid and a head space 16 which contains gas. Head space 16 is disposed above the surface of the liquid in liquid space 14.
• Vessel 12 includes means for measuring the
• the temperature measuring means comprises any known temperature measuring device, such as a thermocouple.
• the temperature measuring device such as a thermocouple.
• measuring means is a resistance temperature device (RTD).
• RTD resistance temperature device
• the gas in the head space of all the embodiments of the present invention is typically air which is present in the system when the system begins its operation.
• the liquid in the liquid space of all the embodiments may be wastewater or any other liquid for which it is desirable to monitor the concentration of weakly soluble
• the system of all the embodiments of the present invention is applicable to any weakly soluble material including
• chlorocarbons such as carbon tetrachloride and chloroform, aromatic and aliphatic hydrocarbons, and other halogenated materials.
• the system of the present invention further includes liquid inlet means disposed in communication with the vessel for injecting a stream of the liquid into the vessel.
• the liquid inlet means includes an inlet port 18 formed in vessel 12, a liquid inlet conduit 20 disposed in communication with liquid inlet port 18, a liquid inlet manifold 22 disposed in communication with inlet conduit 20 and first and second liquid supply pipes 24, 26 disposed in communication with inlet manifold 22.
• first and second liquid supply pipes 24, 26 disposed in communication with inlet manifold 22.
• Supply pipes 24, 26 are respectively supplied from at least one possibly distant sample point, such as an effluent ditch, which it is desirable to
• Liquid supply pipes 24, 26, fed under pressure by remote pumps, are fitted with
• by-passes not shown, so that sampled liquid flows continuously, whether it is admitted to manifold 22 or not.
• These by-passes are connected to a common or a separate disposal conduit, also not shown, for return to the at least one distant sample point.
• Supply pipes 24, 26 are provided with first and second shut-off valves 28, 30, respectively, for admitting liquid into vessel 12. The flow of liquid through the system is indicated by the direction of the arrows shown in Fig. 1.
• Valves 28, 30 operate in sequence so that valve 28 is opened to bring in a first sample of the liquid and is then shut off before valve 30 is opened to bring in a second sample of liquid.
• Bubbles 32 contain gas from head space 16 which is entrained in the liquid. These bubbles coalesce, rise to the surface of the liquid and enter head space 16. The bubbles provide an increased surface area of liquid/gas contact for increasing the already occurring transfer of the volatile material from the liquid phase to the gas phase.
• injecting the stream of liquid creates turbulence in the liquid. This turbulence provides agitation, which further enhances the already occurring transfer of the volatile material from the liquid phase to the gas phase. The bubbles and the turbulence cause foam to be formed in the vessel. An anti-foaming agent may be added to vessel 12 to break up this foam.
• concentration of volatile material dissolved in a liquid further comprises liquid outlet means.
• the liquid outlet means includes a liquid outlet port 34 formed in vessel 12 and a liquid discharge conduit 36 disposed in communication with liquid outlet port 34. As bubbles 32 rise to the surface of the liquid, liquid flows through outlet port 34 and liquid discharge conduit 36. Liquid discharge conduit 36 is configured to maintain the volume of the liquid within vessel 12 constant.
• the present invention comprises means for removing a portion of the gas contained within the head space from the vessel.
• Exit conduit 38 is disposed in the upper portion of the wall of vessel 12 and communicates with head space 16.
• Air pump 40 is disposed in conduit 38 and provides suction in head space 16 to pump the gas in head space 16 out of vessel 12 and into exit conduit 38 for circulation in system 10.
• concentration of volatile material dissolved in a liquid further comprises a condenser for removing condensation from the gas removed from the head space and a liquid detector for detecting the level of condensation in the condenser.
• a condenser 42 is provided in exit conduit 38 upstream of air pump 40, and a liquid detector 44 is also provided in exit conduit 38 downstream of condenser 42.
• Condenser 42 removes condensation, if any, from the gas which is removed from head space 16. This condensation occurs because the liquid in vessel 12 is slightly warm and is thus saturated at a higher temperature than ambient. When this liquid is cooled to ambient as it exits the vessel, condensation forms on the interior walls of exit conduit 38.
• Liquid detector 44 is used to detect the level of condensation in
• condenser 42 Normally, the condensation in condenser 42 drains continuously through a drain 46, as shown in Fig. 1, which is configured as an external liquid seal to isolate the system from the atmosphere.
• means for introducing water into the vessel As shown in Fig. 1, the means for introducing water into the vessel
• Flush conduit 48 brings in a supply of "clean" water to clean any previously used liquid sample which is present at the start of a cycle of operation of system 10.
• “Clean” in this context means merely that this water is not from a wastewater stream; this water is not necessarily potable.
• Flush conduit 48 is provided with a shut-off valve 50 for admitting "clean” water.
• “Clean” water can be substituted for a sample at any time to flush the system of impurities, and so that the response time of the entire system may be easily checked with a clean system.
• measuring means comprises an instrument, which is shown generally at 52 in Fig. 1.
• Instrument 52 measures the concentration of the volatile material in the portion of the gas removed from head space 16.
• Instrument 52 may employ various known methods of detection. The specific method and device used with the present invention are dependent on the volatile material which is measured.
• Instruments suitable for use with the system of the present invention include a prism or grating instrument, a mass spectrometer and a plasma or gas
• Instrument 52 may employ other methods such as non-dispersive filter photometry and Fourier transform infrared (FTIR) monitoring.
• FTIR Fourier transform infrared
• An instrument which is preferred for use with the present invention is commercially available from Laser Precision Analytical and is sold under the trademark "PCM-4000". This instrument obtains a gas phase spectrum from the gas removed from the head space.
• the present invention further comprises means for calculating a gas phase concentration value from the measured concentration and for converting the gas phase concentration value to a liquid phase concentration value.
• the calculation and conversion means includes a computer 53.
• computer 53 is a microprocessor.
• Computer 53 calculates a gas phase concentration value for the material from the measured
• the preferred Laser Precision instrument includes proprietary Laser Precision software, which the present invention employs and supplements to make this conversion as will be explained in greater detail below.
• means for introducing air to the instrument to zero the instrument there is provided means for introducing air to instrument 52
• Three-way inlet valve 58 includes a first branch 58a and a second branch 58b.
• the present invention further comprises means for venting the air introduced by the air introduction means.
• the venting means includes a three-way outlet valve, shown generally at 60, disposed downstream of instrument 52.
• Three-way outlet valve 60 includes a first branch 60a and a second branch 60b.
• valve 58a and 60a are opened and second branches 58b and 60b are closed, air is introduced from valve 56 through inlet valve 58, flows through instrument 52 and is allowed to escape to the atmosphere through outlet valve 60.
• by-pass valve 62 is opened to allow continuous circulation of the gas removed from head space 16 through by-pass conduit 54. This ensures that pressure does not build up in air pump 40.
• first branches 58a and 60a are closed and second branches 58b and 60b are opened, the portion of the gas removed from head space 16 flows through exit conduit 38 to instrument 52.
• the system of the present invention for monitoring the concentration of volatile materials in a liquid further comprises a dryer for drying moisture in the gas removed from the head space.
• a dryer shown at 64 in Fig. 1, is disposed in exit conduit 38 upstream of instrument 52.
• the presence of moisture in the portion of the gas removed from head space 16 will not affect the concentration reading of the gas measured by instrument 52, it tends to damage the components of the system. Thus, it is often desirable to remove this moisture with dryer 64.
• the use of a dryer is purely optional.
• the present invention includes means for re-introducing the measured gas into the vessel.
• the means for re-introducing the measured gas into vessel 12 includes a re-entry conduit 66.
• Re-entry conduit 66 introduces the gas which has been removed from head space 16 and monitored by instrument 52 into the liquid of liquid space 14.
• the action of introducing the gas into liquid space 14 creates bubbles 33, which coalesce, rise to the surface of the liquid and enter head space 16. This enhances the already occurring transfer of the volatile material from the liquid phase to the gas phase by creating an increased surface area of liquid/gas contact and thus returning the gas removed from the head space back to the head space.
• the action of introducing the gas into the liquid of liquid space 14 also creates turbulence in the liquid, which further increases the already occurring transfer of
• the system of the present invention thus utilizes the liquid sampled to continuously enhance the transfer of material from the liquid phase to the gas phase. Moreover, the action of introducing the gas into the liquid completes a re-circulating loop to and from the vessel. The re-circulating loop allows the concentration of the material in the gas in head space 16 to be continuously measured. This continuous sampling of the gas from the head space provides multiple opportunities for the material to be transferred from the liquid phase to the gas phase, ensuring that equilibrium is reached
• the system of the present invention further includes a bubbler for compensating for inadvertent changes in the quantity of gas in the vessel, the liquid inlet means, the liquid outlet means, the gas removing means, the monitoring instrument and the gas re-introduction means.
• a bubbler 68 is disposed in communication with head space 16 by a pressure conduit 70.
• Bubbler 68 comprises two bulbs 68a and 68b, connected by a tube 68c.
• Bulbs 68a and 68b contain a liquid, preferably water, which is at the same level in both bulbs at the beginning of operation of the system. Bulbs 68a and 68b are transparent for visual confirmation of the water level therein by the operator of the system.
• the gas in head space 16 will be sucked into bulb 68a, so that liquid in bulb 68a is sucked into bulb 68b through tube 68c. Again, visible bubbles in the bubbler will indicate continued flow until equilibrium pressure is reached.
• the method comprises injecting a stream of the liquid into vessel 12 at a sufficient velocity to create bubbles 32 and turbulence in the liquid, thereby enhancing the transfer of the volatile material from the liquid phase to the gas phase.
• the liquid is then discharged from vessel 12 through liquid outlet means including liquid outlet port 34 and liquid discharge conduit 36.
• a portion of the gas contained in head space 16 is removed therefrom by air pump 40 through exit conduit 38.
• the gas removed from head space 16 is condensed in condenser 42, and the level of the liquid in condenser 42, if any, is automatically detected by liquid detector 44. Condensation which accumulates in the bottom of condenser 42 is normally drained continuously by drain 46.
• the system is flushed of impurities and the response time of the system is checked by admitting "clean" water through flush valve 50 and flush conduit 48.
• Bubbler 68 Bubbler 68
• by-pass valve 62 is opened to allow continuous circulation of the gas removed from head space 16 through the system, and shut-off valve 56 and first branches 58a and 60a are opened, and second
• branches 58b and 60b are closed as shown in Fig. 1 to allow air to flow to inlet three-way valve 58, through instrument 52 and to the atmosphere through three-way outlet valve 60.
• second branches 58b and 60b are opened, and first brahcnes 58a, 60a, shut off-valve 56 and by-pass valve 62 are closed to send the gas removed from head space 16 to instrument 52.
• Moisture from the gas is optionally removed by dryer 64.
• Computer 53 calculates a gas phase concentration value and converts this value to a liquid phase concentration value.
• the gas removed from the head space is then sent to re-entry conduit 66.
• Re-entry conduit 66 re-introduces the gas into vessel 12 and creates bubbles 33 and turbulence in the liquid, thereby continuing to enhance the transfer of the volatile material from the liquid phase to the gas phase. The cycle is then repeated when second shut-off valve 30 is opened and a second sample of the liquid is brought into vessel 12.
• Fig. 2 illustrates a second embodiment of the present invention. Wherever possible, the same reference numerals as those used with respect to the embodiment of Fig. 1 will be used to illustrate like components of the system of the second
• System 10' comprises a vessel 12' including a liquid space 14' containing a sample of the liquid and a head space 16' containing gas disposed above the surface of the liquid.
• the system of the present invention further includes liquid inlet means for introducing a sample of liquid into the vessel.
• the liquid inlet means includes an inlet port 18' formed in vessel 12' and disposed in communication with head space 16', a liquid inlet conduit 20' disposed in communication with liquid inlet port 18', a liquid inlet manifold 22' disposed in communication with liquid inlet conduit 20' and a first and asecond liquid supply pipes 24', 26' disposed in
• the system of the second embodiment of the present invention comprises liquid outlet means including a liquid outlet port formed in the vessel and a liquid discharge conduit disposed in
• the liquid outlet means includes a liquid outlet port 34' formed in vessel 12' and a liquid discharge conduit 36' disposed in communication with liquid outlet port 34', and which operate in the same manner as like components in the embodiment of Fig. 1. As discussed above with respect to the first
• the outlet discharge conduit is
• the present invention comprises means for removing a portion of the gas contained in the head space from the vessel, a condenser and a liquid detector.
• the means for removing a portion of the gas includes an exit conduit 38' and an air pump 40'.
• a condenser 42' including a liquid drain 46' is provided in exit conduit 38' upstream of air pump 40' and a liquid detector 44' is also provided in exit
• conduit 38' downstream of condenser 42' for the same purpose as like components in the embodiment of Fig. 1.
• introducing water into vessel 12' comprises a flush conduit 48' and a shut-off valve 50' which function to clean the system in the same manner as like components in the embodiment of Fig. 1.
• a bubbler 68' is disposed in communication with head space 16' and compensates for any changes in the quantity of gas in system 10' in the same manner as bubbler 68 of the embodiment of Fig. 1.
• the system of the second embodiment of the present invention further includes an means for measuring the concentration of the material in the gas removed from the head space and means for calculating a gas phase concentration value and for converrting the gas phase concentration value to a liquid phase concentration value.
• the measuring means comprises an instrument 52', and the
• calculation and coversion means comprises a compute 53', which function in like instrument 52 and computer 53, respectively, of the embodiment of Fig. 1.
• An optional dryer 64' may be included in the system of the second embodiment for removing moisture from the gas removed from the head space before it is sent to instrument 52'.
• the system of the second embodiment further includes means for introducing air to the instrument to zero the instrument and means for venting the air introduced to the instrument.
• the air introduction means includes a by-pass conduit 54', an air shut-off valve 56', a three-way inlet valve 58' and a by-pass valve 62'.
• the venting means comprises a three-way outlet valve 60'. The air introduction means and the venting means operate in the same manner as like components in the embodiment of Fig. 1.
• the gas re-introduction means includes a re-entry conduit 66' which re-introduces the gas which has been monitored by instrument 52' into vessel 12'.
• Re-entry conduit 66' is similar to re-entry conduit 66 of the embodiment of Fig. 1. However, in the embodiment of Fig. 2, re-entry conduit 66' and frit 72 are the primary source of enhanced transfer of the volatile material from the liquid phase to the gas phase, whereas in the first embodiment, the liquid inlet means are the primary source of enhanced transfer, and the re-entry conduit is only a secondary source of enhanced transfer.
• Re-entry conduit 66' includes a first portion 66a disposed in liquid space 14', a second portion disposed in head space 16' and a third portion 66c disposed between instrument 52' and vessel 12'.
• a porous frit 72 is disposed in first portion 66a of conduit 66'. Frit 72 creates bubbles 33' in the liquid in liquid space 14' which are smaller and more profuse than bubbles 32 and 33 in the embodiment of Fig. l and which thus have a greater total surface area for increasing the transfer of the material from the liquid phase to the gas phase. Bubbles 33' coalesce, rise to the surface of the liquid and enter head space 16', thereby returning the gas removed from head space 16' back to the head space. If necessary, an anti-foaming agent may be added to vessel 12' to break up the foam caused by the turbulence in the liquid.
• a method for monitoring the concentration of volatile material dissolved in a liquid in accordance with this method, a sample of the liquid is introduced via liquid inlet manifold 22', liquid inlet conduit 20' and liquid inlet port 18' into vessel 12', which includes liquid space 14' containing the liquid and head space 16' containing a gas disposed above the surface of the liquid. A portion of the gas is then removed from the head space by air pump 40' through exit conduit 38'. The gas is then condensed by condenser 42' and the level of
• condensation in the condenser is detected by liquid detector 44'. Any condensation which accumulates in condenser 42' is continuously drained by conduit 46'. The system is flushed of impurities and the response time of the system is checked by admitting "clean" water through flush valve 50' and flush conduit 48'. Bubbler 68' compensates for any inadvertent change in the quantity of gas in system 10'.
• shut-off valve 56', by-pass valve 62', second branches 58b' and 60b' are opened, and first branches 58a' and 60a' are closed to allow the concentration of the gas removed from the head space to be measured by instrument 52'.
• the moisture in the gas removed from head space 16' is optionally first dried by dryer 64' before it is measured by instrument 52'.
• Computer 53' then calculates the gas phase concentration value and converts this value to a liquid phase concentration value.
• the gas is then re-introduced into vessel 12' by re-entry conduit 66'.
• the introduction of the gas into the liquid of liquid space 14' creates bubbles 33' and turbulence in the liquid, thereby enhancing the transfer of the material from the liquid phase to the gas phase.
• a third embodiment of a system for monitoring the concentration of volatile material dissolved in a liquid there is provided a third embodiment of a system for monitoring the concentration of volatile material dissolved in a liquid.
• the same reference numerals as those used with respect to the embodiment of Fig. 1 will be used to illustrate like components of the system of the third
• System 10'' comprises a vessel 12'' including a liquid space 14'' containing the liquid and a head space 16" containing gas
• the system of the present invention further includes liquid inlet means disposed in communication with the head space for injecting a stream of the liquid into the vessel.
• the liquid inlet means includes an inlet port 18'' disposed in communication with head space 16'', a liquid inlet conduit 20'' disposed in communication with liquid inlet port 18'', a liquid inlet manifold 22'' disposed in communication with liquid inlet conduit 20'' and a first and a second liquid supply pipe
• First and second liquid supply pipes 24'', 26'' are provided with first and second shut-off valves 28'' and 30''',
• liquid inlet means injects a stream of the liquid into vessel 12'' at a sufficient velocity to create bubbles 32'' and turbulence in the liquid, thereby enhancing the transfer of the material from the liquid phase to the gas phase as discussed above with respect to the first embodiment.
• An anti-foaming agent may be used to break up the foam caused by the turbulence in the liquid.
• the system of the present invention further includes liquid outlet means including a liquid outlet port formed in the vessel and a liquid discharge conduit disposed in communication with the liquid outlet port for discharging the liquid from the vessel.
• the liquid outlet means includes a liquid outlet port 34'' formed in vessel 12'' and a liquid discharge conduit 36'' disposed in communication with liquid outlet port 34'', which operate like corresponding components in the embodiments of Figs. 1 and 2.
• the outlet discharge conduit is configured to maintain the volume of the liquid within the vessel
• the system according the third embodiment of the present invention further comprises means for removing a portion of the gas contained in the head space, a condenser, a liquid detector and means for introducing water into the vessel.
• the means for removing a portion of the gas includes an exit conduit 38'' and an air pump 40''.
• an external source of pressure may be substituted for air pump 40''.
• a condenser 42'' including a drain 46'' is provided in exit conduit 38'' upstream of air pump 40'', and a liquid detector 44'' is also provided in exit conduit 38'' downstream of condenser 42'' for the same purpose as like components in previous
• the means for introducing water into vessel 12'' comprises a flush conduit 48'' and a shut-off valve 50'' which function to clean and check the response time of the system in the same manner as like components in the first and second embodiments.
• the system of the third embodiment of the present invention further includes means for measuring the concentration of the material in the gas removed from the head space and means for calculating the gas phase concentration value and converting the gas phase concentration value to a liquid phase contration value.
• the measuring means comprises an instrument 52'' and the calculation and conversion means comprises a computer 53'' which function as do like components in the
• An optional dryer 64'' for removing the moisture of the gas removed from head space 16'' before it is measured by instrument 52'' is included in exit conduit 38'' upstream of the instrument.
• the third embodiment of the system of the present invention further includes means for discharging the monitored gas to the atmosphere.
• monitored gas comprises a by-pass line 54'', an air shut-off valve 56'', a three-way inlet valve 58'', a three-way outlet valve 60'' and a by-pass valve 62'' as shown in Fig. 3.
• Three-way inlet valve 58'' includes a first branch 58a'' and a second branch 58b "
• three-way outlet valve 60'' includes a first branch 60a " and a second branch 60b''. If it is necessary to zero instrument 52'', shut-off valve 56'' is opened to allow air to flow to three-way inlet valve 58'', and by-pass valve 62'' is opened to prevent pressure from building up in air pump 40''. Also, first branches 58a'' and 60a'' are opened and second branches 58b'' and
• 60b'' are closed as shown in Fig. 3 to introduce air to instrument 52'' to zero the instrument. The air and is then discharged to atmosphere through first branch 60a'' of three-way outlet valve 60''.
• by-pass valve 62'' is closed and first branches 58a'' and 60a'' are closed and second branches 58b'' and 60b'' are opened,
• instrument 52'' measures the concentration of material in the gas removed from head space 16''. The gas is then discharged to the atmosphere
• a stream of the liquid is injected into vessel 12'', which includes liquid space 14'' containing the liquid and head space 16''
• System 10'' may be flushed of impurities and the response time of the system may be checked by opening flush valve 50'' and substituting "clean" water through flush conduit 48'' for the liquid in liquid space 14''.
• a portion of the gas contained in head space 16'' is then removed from the head space by air pump 40'' through exit conduit 38''.
• the gas is then condensed by condenser 42'' and the level of liquid in the condenser, if any, is detected by liquid detector 44''. Drain 46'' continuously drains condensation from the condenser. If it is necessary to zero instrument 52'', shut-off valve 56'', by-pass valve 62'' and first branches 58a'' and 60a'' are opened and second branches 58b'' and 60b'' are closed as shown in Fig. 3 to allow air to circulate through instrument 52''.
• the gas removed from head space 16'' is discharged from system 10'' through by-pass conduit 54'', which prevents pressure from building up in pump 40''.
• first branches 58b'' and 60b'' are closed and second branches 58b'' and 60b'' are opened,
• instrument 42'' measures the concentration of material in the gas removed from head space 16'', and the gas is allowed to escape to the atmosphere through first branch 60a'' of three-way outlet valve 60''.
• Computer 53'' calculates the gas phase concentration value and converts this value to a liquid phase concentration value.
• the moisture in the gas removed from head space 16'' may first be removed by dryer 64'' before the gas is sent through instrument 52''. The cycle is repeated when second shut-off valve 30'' is opened and a second sample of the liquid is brought into vessel 12''.
• the systems of the present invention rely on the following relationships to indirectly measure the concentration of material dissolved in a liquid.
• CCI 4 carbon tetrachloride
• a, b, c and d are known constants (See Horvath, Halogenated Hydrocarbons - Solubility -Miscibility with Water, Dekker, New York (1982))
• Fig. 4 is a flowchart showing the computations for calculating a gas phase
• Block 1 of Fig. 4 shows the step of obtaining a gas phase spectrum.
• the proprietary software included with the preferred Laser Precision instrument included with the preferred Laser Precision instrument
• This gas phase concentration value is then inputted to the computer program of the present invention, which uses the Henry's law (equation (1) above) to calculate a liquid phase concentration value.
• the computer program thus supplements the proprietary software.
• the temperature of the liquid in the vessel which is taken with a temperature measuring device, is converted by the computer program into a value used for calculating P o and C o .
• the values for P o and C o are shown in block 3a in Fig. 4a.
• the liquid phase concentration values are then fed back to and displayed by the proprietary software of the preferred instrument, as indicated by block 4 in Fig. 4.
• the displayed liquid phase concentration values are then stored as indicated in block 5 in Fig. 4 by the proprietary software of the preferred instrument for future reference and comparison.
• the displayed values may be viewed by a plant operator. If an excursion of the system has occurred, the operator of the system may then sound an alarm, or the alarm may be automatically sounded, as indicated in block 6 of Fig. 4 to shut down the system.
• FIG. 5 A typical plot of a sample analysis of wastewater for CCI 4 and CHCl 3 during an intentional excursion of the wastewater in the system of the first embodiment of the present invention is shown in Fig. 5.
• the concentration of CCI 4 as a function of time is shown by the solid line and the
• concentration of CHCI 3 as a function of time is shown by a dot-dash line.
• the zero reference point of instrument 52 is shown by the dashed line.
• the time marked T 1 represents the point where a
• the analyzer begins an automatic zeroing operation, in which fresh air is introduced into instrument 52 in place of a circulating air sample through shut-off valve 56, and three-way valves 58 and 60. After sufficient flushing, the instrument is re-zeroed.
• FIG. 6 A typical plot of a sample analysis of wastewater for CCl 4 and CHCl 3 during an inadvertent excursion of the wastewater in the system of the first embodiment of the present invention is shown in Fig. 6.
• excursions such as those shown at T 8 through T 12 , represent automatic instrument re-zeroing.
• Addr is rack address 0 - 255
• Channel is module number 1 - 16 on rack ⁇
• VAR Param2, InVal, Code, Result integer
• VAR j,k integer
• Cur_yr, Cur_mo,Cur_day,Cur_dow word;
• DirectVideo : FALSE
• a : 0.1008065*(InVal - 2111) - 100;
• C0 : CLC0 + CLC1 *Temp + CLC2 * Temp*Temp + CLC3 *Temp * Temp *Temp ;

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• 1990
  • 1990-10-26 US US07/603,941 patent/US5222032A/en not_active Expired - Fee Related
• 1991
  • 1991-10-25 DE DE69117302T patent/DE69117302T2/de not_active Expired - Fee Related
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